add user tracking - number of posts + date of last post

[jbensal-zz]

Not sure where to store this, maybe add a field to a user's profile. I don't know how to do this but I will figure it out!

[ben-ng]

one way is to compute this data when you need it, and cache the results in redis.

i suggest this because "total contributions, ever" is a not very useful statistic. "most prolific, last 7 days" is a more meaningful stat, and that stat depends on what the current time is, so you can't track it and save it in mongo.